Osmoregulation as a selection criterion for drought tolerance in wheat

1983 ◽  
Vol 34 (6) ◽  
pp. 607 ◽  
Author(s):  
JM Morgan
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Water Deficit ◽  
Relative Water Content ◽  
Flag Leaf ◽  
Single Gene ◽  
Selection Criterion ◽  
Breeding Lines ◽  
Intermediate Group ◽  
Relative Water

A method is described in which measurements of osmoregulation made on glasshouse-grown wheat plants may be used to select lines which yield higher under conditions of water deficit in the field. The procedure involved growing F4 breeding lines in pots in a semi-controlled glasshouse. When the plants reached booting stage, they were transferred to a controlled environment chamber and droughted by withholding water. During the water deficit cycle approximately 10 flag leaf samples from each line were taken, and measurements were made of relative water content, osmotic potential and water potential. The lines were evaluated using estimates of the relative water content at either osmotic or water potential values of -2.5 MPa, after relationships between these measurements and relative water content had been established. The distribution of data into two main groups with a smaller intermediate group indicated possible single gene control. Under drought conditions in the field, lines selected from the high osmoregulating group maintained turgor to lower water potentials and gave grain yields which were 1.6 and 1.5 times greater than those selected from the low group at the F4 and F6 stages respectively.

scholarly journals Effect of Water Deficit at Vegetative and Reproductive Stages of Hybrid, Open Pollinated Variety and Local Maize (Zea mays L.)

2005 ◽  
Vol 26 ◽  
pp. 37-42 ◽  
Author(s):  
SK Sah ◽  
OB Zamora
Keyword(s):  
Grain Yield ◽  
Water Potential ◽  
Water Content ◽  
Water Deficit ◽  
Relative Water Content ◽  
Harvest Index ◽  
Dry Matter ◽  
Kernel Number ◽  
Kernel Size ◽  
Relative Water

A pot experiment was conducted to study the effects of water deficit on vegetative and reproductive stages of Hybrid, Open pollinated (OPV) and Local varieties of maize. Water deficit at vegetative stage significantly reduced plant height, leaf area, shoot dry matter, root dry matter of the upper 25 cm depth, kernel number and grain yield per plant as compared to well watered plant. Water deficit at reproductive stage reduced more leaf area, kernel number and grain yield per plant than water deficit at vegetative stage. Water deficit at reproductive stage also reduced shoot dry matter, kernel size and harvest index. Leaf water potential and relative water content taken at 58 and 60 days after planting were also reduced by water deficit. The Local variety was taller with smaller kernel size and lower harvest index than Open pollinated and Hybrid varieties. There were no significant interactions among the varieties and water deficit treatments. Key words: Leaf water potential, relative water content, vegetative and reproductive stages, harvest index J. Inst. Agric. Anim. Sci. 26:37-42 (2005)

A Gene Controlling Differences in Osmoregulation in Wheat

1991 ◽  
Vol 18 (3) ◽  
pp. 249 ◽  
Author(s):  
JM Morgan
Keyword(s):  
Water Content ◽  
Osmotic Potential ◽  
Relative Water Content ◽  
Flag Leaf ◽  
Single Gene ◽  
Recessive Gene ◽  
Single Chromosome ◽  
Relative Water ◽  
Environment Chamber ◽  
Response To Water

Evidence is presented for a single gene controlling differences in osmoregulation in wheat in response to water stress, confirming earlier results. Analyses of osmoregulation were made on the flag leaves of wheat plants which were grown in pots in the glasshouse and stressed in a controlled environment chamber by withholding water after the flag leaf had fully emerged. Osmoregulation was derived from responses of osmotic potential to relative water content or from responses of relative water content and osmotic potential to water potential. Usable estimates of osmoregulation were obtained for 67 F2 lines derived from contrasting parents, to test for gene number, and for one substitution series with contrasting parents, to determine chromosomal location. The F2 frequency response, which consisted of two overlapping distributions, was compatible with a single recessive gene, the estimated ratio being 2.79 : 1 (low: high osmoregulation). This confirmed previous measurements made on F1s and F4s Results for the substitution series were also compatible with these results in indicating a single chromosome, 7A, which had an identical response to the low osmoregulation parent, Red Egyptian. The effects of the gene were confined to solute accumulations at water potentials above, but not below, zero turgor.

scholarly journals Physiological and morphological traits associated with germinative and reproductive stage of garden orache (A. hortensis L. var. rubra) under water stress

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
S. Sai Kachout ◽  
S. BenYoussef ◽  
A. Ennajah ◽  
S. Abidi ◽  
A. Zoghlami
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Water Deficit ◽  
Relative Water Content ◽  
Water Regime ◽  
Physiological Parameters ◽  
Reproductive Stage ◽  
Relative Water ◽  
Number Of Branches

Abstract Background Drought is a major problem limiting the growth and development of plants in the world and especially in Tunisia. Halophytes constitute a renewable wealth and they offer great flexibility with regard to abiotic stresses, and they are evaluated for their ecological and potential food use. Results The proposed work identifies the response of Atriplex hortensis var. rubra to the germinal stage and the reproductive stage under a deficient water regime to measure the drought resistance of this plant that has very interesting forage production abilities. The morphological and water parameters are used to characterize the physiological response of this species to the effects of water deficit. For the germination test, four levels of osmotic potential caused by PEG-6000 solutions at different levels of water potential (− 0.1, − 0.5, − 1.0, − 1.5 MPa) were adopted in seed of A. hortensis germination media. The methodology adopted in the second experiment is based on the cultivation of potted plants stored in a semi-controlled greenhouse at flowering stage. The water deficit was imposed on the plants by watering stop for a week, and the control plants are subjected to a water regime maintained irrigated at 100% of the capacity in the field. Drought tolerance was scored 30 days after the drought stress commenced based on the number of branches and leaf, dry biomass, relative water content, leaf water potential, and nitrogen content. No significant difference was observed in germination rates for all PEG concentrations throughout the experiment which are still close to 60%. The results obtained for the second experiment show a high tolerance of A. hortensis under water stress. Drought induced decreases in two physiological parameters, the number of branches and leafs, and the relative water content of annual Atriplex. Heatmap and PCA data revealed that physiological parameters are more sensitive than morphological parameters in distinguishing the control and drought treatments. Conclusions Indeed, the orache is distinguished by a great ability to retain water potential after a month of stress. Thus, height, number of branches, leaf and shoot dry weight, and percentage of nitrogen were significantly similar for controls and stressed for A. hortensis. On the other hand, measured root length and basic and midday water potential show significant variability between controls and stressors. In addition, these results highlight the importance of the resistance of Atriplex halophyte forage to drought.

scholarly journals Growth and physiological response of two biomass sorghum (Sorghum bicolor (L.) Moench) genotypes bred for different environments, to contrasting levels of soil moisture

2015 ◽  
Vol 10 (4) ◽  
pp. 208 ◽  
Author(s):  
Lorenzo Barbanti ◽  
Ahmad Sher ◽  
Giuseppe Di Girolamo ◽  
Elio Cirillo ◽  
Muhammad Ansar
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Aboveground Biomass ◽  
Relative Water Content ◽  
Physiological Response ◽  
Field Capacity ◽  
Biomass Sorghum ◽  
Relative Water

A better understanding of plant mechanisms in response to drought is a strong premise to achieving high yields while saving unnecessary water. This is especially true in the case of biomass crops for non-food uses (energy, fibre and forage), grown with limited water supply. In this frame, we investigated growth and physiological response of two genotypes of biomass sorghum (<em>Sorghum bicolor</em> (L.) Moench) to contrasting levels of soil moisture in a pot experiment carried out in a greenhouse. Two water regimes (high and low water, corresponding to 70% and 30% field capacity) were applied to JS-2002 and Trudan-8 sorghum genotypes, respectively bred for dry sub-tropical and mild temperate conditions. Two harvests were carried out at 73 and 105 days after seeding. Physiological traits (transpiration, photosynthesis and stomatal conductance) were assessed in four dates during growth. Leaf water potential, its components and relative water content were determined at the two harvests. Low watering curbed plant height and aboveground biomass to a similar extent (ca. 􀀀70%) in both genotypes. JS-2002 exhibited a higher proportion of belowground to aboveground biomass, <em>i.e</em>., a morphology better suited to withstand drought. Despite this, JS-2002 was more affected by low water in terms of physiology: during the growing season, the average ratio in transpiration, photosynthesis and stomatal conductance between droughty and well watered plants was, respectively, 0.82, 0.80 and 0.79 in JS-2002; 1.05, 1.08 and 1.03 in Trudan-8. Hence Trudan-8 evidenced a ca. 20% advantage in the three traits. In addition, Trudan-8 could better exploit abundant moisture (70% field capacity), increasing aboveground biomass and water use efficiency. In both genotypes, drought led to very low levels of leaf water potential and relative water content, still supporting photosynthesis. Hence, both morphological and physiological characteristics of sorghum were involved in plant adaptation to drought, in accordance with previous results. Conversely, the common assumption that genotypes best performing under wet conditions are less suited to face drought was contradicted by the results of the two genotypes in our experiment. This discloses a potential to be further exploited in programmes of biomass utilization for various end uses, although further evidence at greenhouse and field level is needed to corroborate this finding.

Relative water content and water potential of tissue 1

1995 ◽  
Vol 46 (1) ◽  
pp. 111-118 ◽  
Author(s):  
J.C. Diaz-Pérez ◽  
K.A. Shackel ◽  
E.G. Sutter
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Relative Water Content ◽  
Relative Water

Studies on the Status of Unburnt Eucalyptus Woodland at Ocean Grove, Victoria. V. The Interactive Effects of Droughting and Shading on Seedlings Under Competition.

1979 ◽  
Vol 27 (3) ◽  
pp. 285 ◽  
Author(s):  
JR Withers
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Drought Resistance ◽  
Relative Water Content ◽  
Height Growth ◽  
Interactive Effects ◽  
Wide Range ◽  
Relative Water ◽  
Pre Treatment ◽  
Grass Sward

Casuarina littoralis seedlings are inherently more drought-resistant than Eucalyptus ovata seedlings over a wide range of environmental conditions. Moderate shade pre-treatment (30% of full daylight) decreased the drought resistance of seedlings of E. ovata, Acacia pycnantha and C. stricta but not that of C. littoralis seedlings. Deep shade pre-treatment (8 % of full daylight) decreased the drought resistance of all species and was associated with decreased rootlshoot ratios. Both shaded and non-shaded C. littoralis seedlings closed stomata at higher relative water contents (about 80% and 88 % respectively) than did E. ovata seedlings (about 36 % and 63 % respectively). Shading decreased the relative water content at which E. ovata closed stomata and reduced the relative decrease in water potential which occurred with unit decreases in relative water content. When E. ovata and C. littoralis seedlings were grown in competition, the larger E. ovata dominated the drought response of plants under both high and low light conditions. E. ovata rapidly depleted moisture supplies thereby subjecting C. littoralis to greater stress and earlier death than it experienced in monoculture. C. littoralis seedlings grown and droughted in competition with E. ovata exhibited smaIIer decreases in water potential per unit decrease in relative water content than seedlings grown in monoculture. The height growth of E. ovata grown in monoculture and in competition with C. littoralis was reduced for at least 10-15 weeks after the wilting treatment, but height growth of C. littoralis was not affected. Eucalypts wilted at higher water potentials (-4.3 MPa) than did C. littoralis seedlings (- 6.3 MPa). It is suggested that the replacement of E. ovata by C. littoralis at Ocean Grove, Vic. may be partly due to the differential effects of shading on the drought resistance of seedlings which become established in the grass sward of canopy gaps.

scholarly journals Shading as a means of mitigating water deficit in seedlings of Campomanesia xanthocarpa (Mart.) O. Berg

2020 ◽  
Vol 48 (1) ◽  
pp. 234-244
Author(s):  
Edinéia M.M. BARTIERES ◽  
Silvana P.Q. SCALON ◽  
Daiane M. DRESCH ◽  
Edvânia A.S. CARDOSO ◽  
Mailson V. JESUS ◽  
...  
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Relative Water Content ◽  
Growth Characteristics ◽  
Water Deficiency ◽  
Cultivation Conditions ◽  
Continuous Irrigation ◽  
Intermittent Irrigation ◽  
Relative Water ◽  
Number Of Leaves

In this research it was hypothesized that Campomanesia xanthocarpa can overcome some level of water deficiency by adjusting physiological parameters and that shading minimizes the water deficit effects while maintaining elevated photosynthetic rates and relative water content of the leaves and makes a resumption of metabolism and growth when the water supply is normalized. The seedlings were submitted to two water regimes (continuous irrigation - CI and intermittent irrigation - II), three shading percentages (0, 30 and 70%) and six evaluation times (Start - T0, 1st Photosynthesis Zero - 1st P0, 1st Recovery - 1st REC, 2nd Photosynthesis Zero - 2nd P0, 2nd Recovery - 2nd REC and END). Plants under water deficit at 0% shading led to a reduction in photosynthetic metabolism, relative water content (RWC), leaf area, number of leaves, and height, especially during the stress periods 1st and 2nd P0. The 30 and 70% shading mitigated the stressful effect of water deficit on C. xanthocarpa seedlings. The results did not confirm the hypothesis that C. xanthocarpa seedlings are intolerant to water deficit since, although sensitive, they presented a potential for recovery of photosynthetic and growth characteristics under all cultivation conditions. It was concluded that that shading minimizes the stressful effects of water deficit.

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